K40 module
 

After reading all the posts about the K40 module going out, I wonder if I should just buy one and have it on hand for the inevitable. AFAIK, mine is original. I have some parts credit to use up at the local dealer. Should I add the K40 to my shopping list? My car isn't home right now to look. Is the part number on the unit or does someone have it off the top of their head?

Thanks.

Part number is right on top of the unit. Best to check yours directly. Mine is 210 540 03 72, but my car's a 1996 and I've learned not to assume. Dealer price is somewhere around $125. I'd recommend getting one as a spare, since one of its failure modes shuts the engine off right in the middle of driving.

Codes
 

When K40 acts up, does it leave a trail that a code reader can come along later (since the failure is intermittent) and find? I have a reader on order; I might as well get some use out of it!

Jeremy

Hmmm, I wonder how gracefully they age? If anything like glow plug relays, keeping one in storage is a bad idea as they age faster when not in use.

If a code is set by the failure of the K40, it will be something completely unrelated.

Len - From memory the part number on our turbos is 01 72.

I think they are all destined to fail. Greater use (mileage) and associated expansion/contraction cycles will cause the printed circuts to crack eventually.

Hmmmmm
 

I can't speak from experience with these specific parts and so don't want to violently disagree with Max....

My experience with electronics in general suggests that
(a) everything ages, even sitting on a shelf
(b) some things age more 'gracefully' than others, as Max implies with his question
(c) the vibration and heat/cool cycles that electronic devices experience in an engine compartment have to be worse than sitting on a shelf or in a car's trunk
(d) any part purchased as a spare and put away will never be used because the part in the car then won't fail (Murphy's Law)

On the other hand, if that is what it takes to make K40 reliable, go for it!

Jeremy

Code Talker
 

You're saying that if a code is set by the failure, I'll be able to read it and clear it but it won't necessarily point to K40? I'll know there was a failure (which I knew already). The only thing I'll learn is that the computer knows that something has happened...I'll be no better off than Apollo 11 was when the computer gave them a "program alarm" 60 seconds before landing on the moon. ("Something is wrong. You guess what it is.") :eek: :D

Jeremy

Such is the nature of the K40 fault. It provides power to numerous devices. If a device fails to activate or report its parameters because it has no power, the device will trip a code, but won't tell you why. That would be too easy.....The key is usually that the faults occur intermittently.

The k40 is like a pandora's box... If in doubt, just replace it. The K40 controls and directly/indirectly affects so many systems. Hence it is known was the achilles heal of the 210 chassis. You should be able to purchase one for around $100.

On a '96, the engine isn't completely controlled by the ECM. On the '97 and up, the fuel injection is completely controlled via computers. If any of that goes out forget about starting the vehicle... Think about that :grim:

The US-spec '96 has a computer-controlled rack modulator and shutoff diverter valve. The '97 isn't any more computerized than that.

Drive by wire for '97 up man... At least partial DBW :-)

You missed my point. The '96 is also DBW. There is no mechanical connection from the throttle pedal to the injection pump.

Terry - I saw a number of 000 540 01 72. It shows up as a relay on the Mercedes price list, $78 MSRP, $60 wholesale. Is that it? The reason I'm asking is that in post #2 above, his part started with 210. Maybe I was looking at the wrong relay, since I've never had to deal with the K40 before. Want to be sure I've got it right before I order one.

Len - Per the Russian EPC 000 540 01 72 is the correct part number. It is #98 on the attached detail and is located in the Right hand apparatus box.

http://detali.ru/cat/oem_mb2.asp?TP=1&F=210025&M=606%2E962&GA=722%2E608&CT=F&cat=45P&SID=54&SGR=040&SGN=03